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            <div><h3 class="title">
                <a name="asio.reference.Sender"></a><a class="link" href="Sender.html" title="Sender concepts">Sender
                concepts</a>
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    <h5>
        <a name="asio.reference.Sender.h0"></a>
        <span><a name="asio.reference.Sender.sender_and_sender_to"></a></span><a class="link"
                                                                                 href="Sender.html#asio.reference.Sender.sender_and_sender_to">sender
        and sender_to</a>
    </h5>
    <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span
            class="keyword">class</span> <span class="identifier">S</span><span class="special">&gt;</span>
  <span class="identifier">concept</span> <span class="identifier">sender</span> <span class="special">=</span>
    <span class="identifier">move_constructible</span><span class="special">&lt;</span><span class="identifier">remove_cvref_t</span><span
                class="special">&lt;</span><span class="identifier">S</span><span class="special">&gt;&gt;</span> <span
                class="special">&amp;&amp;</span>
    <span class="special">!</span><span class="identifier">requires</span> <span class="special">{</span>
      <span class="keyword">typename</span> <span class="identifier">sender_traits</span><span
                class="special">&lt;</span><span class="identifier">remove_cvref_t</span><span
                class="special">&lt;</span><span class="identifier">S</span><span class="special">&gt;&gt;::</span><span
                class="identifier">__unspecialized</span><span class="special">;</span> <span class="comment">// exposition only</span>
    <span class="special">};</span>

<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span
                class="identifier">S</span><span class="special">,</span> <span class="keyword">class</span> <span
                class="identifier">R</span><span class="special">&gt;</span>
  <span class="identifier">concept</span> <span class="identifier">sender_to</span> <span class="special">=</span>
    <span class="identifier">sender</span><span class="special">&lt;</span><span class="identifier">S</span><span
                class="special">&gt;</span> <span class="special">&amp;&amp;</span>
    <span class="identifier">receiver</span><span class="special">&lt;</span><span class="identifier">R</span><span
                class="special">&gt;</span> <span class="special">&amp;&amp;</span>
    <span class="identifier">requires</span> <span class="special">(</span><span class="identifier">S</span><span
                class="special">&amp;&amp;</span> <span class="identifier">s</span><span class="special">,</span> <span
                class="identifier">R</span><span class="special">&amp;&amp;</span> <span
                class="identifier">r</span><span class="special">)</span> <span class="special">{</span>
      <span class="identifier">execution</span><span class="special">::</span><span
                class="identifier">connect</span><span class="special">((</span><span class="identifier">S</span><span
                class="special">&amp;&amp;)</span> <span class="identifier">s</span><span class="special">,</span> <span
                class="special">(</span><span class="identifier">R</span><span class="special">&amp;&amp;)</span> <span
                class="identifier">r</span><span class="special">);</span>
    <span class="special">};</span>
</pre>
    <p>
        None of these operations shall introduce data races as a result of concurrent
        invocations of those functions from different threads.
    </p>
    <p>
        A sender type's destructor shall not block pending completion of the submitted
        function objects.
    </p>
    <p>
        [<span class="emphasis"><em>Note:</em></span> The ability to wait for completion of submitted
        function objects may be provided by the associated execution context. —<span class="emphasis"><em>end
        note</em></span>]
    </p>
    <h5>
        <a name="asio.reference.Sender.h1"></a>
        <span><a name="asio.reference.Sender.typed_sender"></a></span><a class="link"
                                                                         href="Sender.html#asio.reference.Sender.typed_sender">typed_sender</a>
    </h5>
    <p>
        A sender is <span class="bold"><strong>typed</strong></span> if it declares what types
        it sends through a receiver's channels. The <code class="computeroutput"><span
            class="identifier">typed_sender</span></code>
        concept is defined as:
    </p>
    <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span
            class="keyword">template</span><span class="special">&lt;</span><span class="keyword">template</span><span
            class="special">&lt;</span><span class="keyword">class</span><span class="special">...&gt;</span> <span
            class="keyword">class</span> <span class="identifier">Tuple</span><span class="special">,</span> <span
            class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span><span
            class="special">...&gt;</span> <span class="keyword">class</span> <span
            class="identifier">Variant</span><span class="special">&gt;</span> <span class="keyword">class</span><span
            class="special">&gt;</span>
  <span class="keyword">struct</span> <span class="identifier">has</span><span class="special">-</span><span
                class="identifier">value</span><span class="special">-</span><span class="identifier">types</span><span
                class="special">;</span> <span class="comment">// exposition only</span>

<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">template</span><span
                class="special">&lt;</span><span class="keyword">class</span><span class="special">...&gt;</span> <span
                class="keyword">class</span> <span class="identifier">Variant</span><span class="special">&gt;</span>
  <span class="keyword">struct</span> <span class="identifier">has</span><span class="special">-</span><span
                class="identifier">error</span><span class="special">-</span><span class="identifier">types</span><span
                class="special">;</span> <span class="comment">// exposition only</span>

<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span
                class="identifier">S</span><span class="special">&gt;</span>
  <span class="identifier">concept</span> <span class="identifier">has</span><span class="special">-</span><span
                class="identifier">sender</span><span class="special">-</span><span
                class="identifier">types</span> <span class="special">=</span> <span
                class="comment">// exposition only</span>
    <span class="identifier">requires</span> <span class="special">{</span>
      <span class="keyword">typename</span> <span class="identifier">has</span><span class="special">-</span><span
                class="identifier">value</span><span class="special">-</span><span class="identifier">types</span><span
                class="special">&lt;</span><span class="identifier">S</span><span class="special">::</span><span
                class="keyword">template</span> <span class="identifier">value_types</span><span
                class="special">&gt;;</span>
      <span class="keyword">typename</span> <span class="identifier">has</span><span class="special">-</span><span
                class="identifier">error</span><span class="special">-</span><span class="identifier">types</span><span
                class="special">&lt;</span><span class="identifier">S</span><span class="special">::</span><span
                class="keyword">template</span> <span class="identifier">error_types</span><span
                class="special">&gt;;</span>
      <span class="keyword">typename</span> <span class="identifier">bool_constant</span><span
                class="special">&lt;</span><span class="identifier">S</span><span class="special">::</span><span
                class="identifier">sends_done</span><span class="special">&gt;;</span>
    <span class="special">};</span>

<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span
                class="identifier">S</span><span class="special">&gt;</span>
  <span class="identifier">concept</span> <span class="identifier">typed_sender</span> <span class="special">=</span>
    <span class="identifier">sender</span><span class="special">&lt;</span><span class="identifier">S</span><span
                class="special">&gt;</span> <span class="special">&amp;&amp;</span>
    <span class="identifier">has</span><span class="special">-</span><span class="identifier">sender</span><span
                class="special">-</span><span class="identifier">types</span><span class="special">&lt;</span><span
                class="identifier">sender_traits</span><span class="special">&lt;</span><span class="identifier">remove_cvref_t</span><span
                class="special">&lt;</span><span class="identifier">S</span><span class="special">&gt;&gt;&gt;;</span>
</pre>
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